Attention, identity thieves: The Manhattan DA is setting up a unit to find out who you are – and who you aren’t.

Identity thefts have risen steadily over the past three years, with about four new felony cases getting prosecuted each day, District Attorney Robert Morgenthau said yesterday.

And the crooks are getting smarter.

In one recent scam, crooked employees at expensive restaurants smuggled in their own credit-card readers to record the card information of wealthy customers.

In another, dishonest company employees would sell credit-card information in bulk to thieves who would use the info to place Internet orders for CD burners. The burners would be used to copy movies that are sold on the street

The unit’s prosecutors and other staffers have received training in identification fraud, credit-card and check fraud, and the use of an ID-theft database to track suspects.

People who believe they have been victimized can call a hot line at (212) 335-9600.